SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7bead8acfbdb4e3388b935f3bf044cdd1587210b3ba929e293a490f0a5de05a' 
  AND token = 'CTspQyeIN6nGD2eObWvVch7cXTZsGObndTlaKi1rU84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}